SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* Merck & Co., Inc. (Last) (First) (Middle) 2000 GALLOPING HILL ROAD (Street) KENILWORTH NJ 07033 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol OPGEN INC [ OPGN ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 05/19/2016
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	05/19/2016		A		1,200,000	A	(1)	2,679,022	I	See Footnote(2)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Warrants	$1.3125	05/19/2016		P		900,000		08/17/2016	05/19/2021	Common Stock	900,000	(1)	900,000	I	See Footnote(2)
Common Stock and Warrants (Obligation to buy Units)	$1.1438	05/19/2016		P		2,734,427		(3)	(3)	Common Stock	4,785,248	(3)	5,685,248	I	See Footnote(2)

1. Name and Address of Reporting Person* Merck & Co., Inc. (Last) (First) (Middle) 2000 GALLOPING HILL ROAD (Street) KENILWORTH NJ 07033 (City) (State) (Zip)

1. Name and Address of Reporting Person* Merck Sharp & Dohme Corp. (Last) (First) (Middle) ONE MERCK DRIVE (Street) WHITEHOUSE STATION NJ 08889 (City) (State) (Zip)

1. Name and Address of Reporting Person* Merck Global Health Innovation Fund, LLC (Last) (First) (Middle) ONE MERCK DRIVE (Street) WHITEHOUSE STATION NJ 08889 (City) (State) (Zip)

Explanation of Responses:

1. The reported securities are included within units ("Units") each Unit consisting of one share of the Company's common stock, par value $0.01 per share (the "Common Stock") and (ii) a warrant to acquire 0.75 of one share of Common Stock for a purchase price of $1.14375 per Unit.

2. These shares are owned directly by Merck Global Health Innovation Fund, LLC ("MGHIF"), which is a wholly owned subsidiary of Merck Sharp & Dohme Corp. ("MSD"), which is a wholly owned subsidiary of Merck & Co., Inc. ("Merck"). MSD and Merck are indirect beneficial owners of the reported securities.

3. Represents future obligation of MGHIF to purchase additional Units for a purchase price of $1.14375 per Unit within 60 days and subject to stockholder consent and notice to stockholders of same (including the filing of Schedule 14C and the twenty day waiting period), pursuant to the Amended and Restated Securities Purchase Agreement entered into on May 18, 2016.

Remarks:

* Ms. Katie Fedosz is signing as Attorney-in-Fact pursuant to power of attorney dated July 23, 2015 granted by each Reporting Person, a copy of which is filed as an exhibit and incorporated herein by reference.

	/s/Katie Fedosz as Attorney-In-Fact*	05/24/2016
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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